Análise de água e efluente de uma indústria têxtil

Abstract

The textile industry, despite its great importance within the manufacturing sector, is a major source of pollution due to the fact that its effluents exhibit characteristics that make degradation difficult, primarily because of the dyes used, which are not fully fixed to the fabrics during the dyeing process. As a result, various treatment methods are employed to minimize the pollutant load of these effluents. Among the most commonly used are physicochemical processes, as well as biological treatments, which have proven effective especially for biodegradable compounds. However, the presence of synthetic dyes, heavy metals, and a high organic load presents additional challenges, requiring the combination of technologies to achieve the desired efficiency. Given this scenario, the treatment of textile effluents becomes an essential step toward the sustainability of the sector, contributing to the preservation of water resources and the reduction of negative environmental impacts. In this context, the objective of this study was to analyze the quality of raw, industrial, and effluent water from a textile industry, verifying its compliance with the limits established by Brazilian environmental resolutions CONAMA No. 357/2005 and COEMA No. 02/2017. Physicochemical analyses were carried out at different stages of the process, including parameters such as pH, electrical conductivity, color, turbidity, iron, silica, chlorides, sulfates, sulfides, total solids, and chemical oxygen demand (COD). The results showed that, despite the partial efficiency of the treatment system—especially in the reduction of color and COD—there were still frequent non-compliances with legal standards, particularly related to COD, true color, and total suspended solids. Additionally, in some cases, an increase in organic load was observed after the biological stage, indicating possible failures in oxygen supply or low microbiological efficiency. The treated industrial water also showed undesirable variations in conductivity and the presence of ions such as iron and silica, which negatively affect dyeing processes. It is concluded that the treatment system requires adjustments, especially in the biological and final polishing stages, and the integration of complementary technologies, such as advanced oxidation processes, is recommended. These improvements are essential to ensure environmental compliance, product quality, and the sustainability of the textile sector.